<h3>年历</h3>
<form action="calendar.php">
  <input type="text" placeholder="请输入四位数年份" name="year">
  <button>提交</button>
</form>
<div id=”calendar“>

</div>
<?php
  /**
   * 获取年份
   */
  if(isset($_GET["year"])){
    $year=$_GET["year"];
  }else{
    $year=2025;
  }
  echo $year."<br>";
  
?>